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A high-stability quasi-spherical resonator in SPRIGT for microwave frequency Measurements at low temperatures

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Science Bulletin 2019年第5期64卷 286-288页

作者： Haiyang Zhang Wenjing Liu Bo Gao Yanyan Chen Changzhao Pan Yaonan Song Hui Chen Dongxu Han Jiangfeng Hu Ercang Luo Laurent Pitre TIPC-LNE Joint Laboratory on Cryogenic Metrology Science and Technology Chinese Academy of Sciences (CAS) Key Laboratory of Cryogenics Technical Institute of Physics and Chemistry (TIPC) Chinese Academy of Sciences (CAS) Laboratoire National de Métrologie Et d’essais-Conservatoire National des Arts et Métiers (LNE-Cnam) School of Mechanical Engineering Beijing Institute of Petrochemical Technology Key Laboratory of Thermo-Fluid Science and Engineering of MOE School of Energy and Power Engineering Xi’an Jiaotong University University of Chinese Academy of Sciences

To meet the de ma nds of high stability and sustainable temperature Measurements over time,TIPC-CAS in China and LNE-Cnam in France have jointly developed single-pressure refractive-index gas thermometiy(SPR1GT),which... 详细信息

关键词： A high-stability quasi-spherical resonator SPRIGT microwave frequency Measurements low temperatures

Three-dimensional finite-time cooperative guidance for multiple missiles without radial velocity Measurements

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Chinese Journal of Aeronautics 2019年第5期32卷 1294-1304页

作者： Teng LYU Chuanjiang LI Yanning GUO Guangfu MA Department of Control Science and Engineering Harbin Institute of Technology

In order to simultaneously attack a target with impact angle constraint in threedimensional(3-D) space, a novel distributed cooperative guidance law for multiple missiles under directed communication topologies is proposed without radial velocity Measurements. First, based on missiles-target 3-D relative motion equations, the multiple missiles cooperative guidance model with impact angle constraint is constructed. Then, in Line-of-Sight(LOS) direction, based on multiagent system cooperative control theory, one guidance law with directed topologies is designed with strict proof, which can guarantee finite time consensus of multiple missiles' impact times. Next, in elevation direction and azimuth direction of LOS, based on homogeneous system stability theory and integral sliding mode control theory, two guidance laws are proposed respectively with strict proof, which can guarantee LOS angles converge to desired values and LOS angular rates converge to zero in finite time. Finally, the effectiveness of the designed cooperative guidance law is demonstrated through simulation results.

关键词： 3-D cooperative guidance Directed communication topologies Finite time Impact angle constraint Radial velocity Measurements

Robust H∞ Fuzzy Output-feedback Control With Both General Multiple Probabilistic Delays and Multiple Missing Measurements and Random Missing Control

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自动化学报 2017年第9期43卷 1656-1664页

作者： Bishan Zhang Zhongjun Ma Meixiang Yang School of Mathematics and Computing Science Guilin University of Electric and Technology Guilin 541004 China

In this paper,the robust H∞-control problem is reported for a class of uncertain discrete-time fuzzy systems with both multiple probabilistic delays and multiple missing Measurements and random missing control from the fuzzy controllers to the actuator.A sequence of random variables including accounting for the probabilistic communication delays and the random missing control are thought as mutually independent and obey the Bernoulli distribution.The measurement-missing phenomenon can be assumed to occur stochastically.Assumption that the missing probability for each sensor satisfies a certain probabilistic distribution in the interval [0 1] is given.Much attention is focused on design of H∞ the fuzzy output feedback controllers to ensure that the resulting close-loop Takagi-Sugeno (T-S) system is exponentially stable in the mean square.The developed method makes disturbance rejection attenuation satisfy a given level by means of the H∞-performance index.Intensive analysis is employed to reach the sufficient conditions about the existence of admissible output feedback controllers which satisfies the exponential stability as well as the prescribed H∞ performance.In addition,the cone-complementarity linearization procedure is utilized to transform the controller-design problem into a sequential minimization one which can be solved by the semi-definite program method.Simulation results conform the feasibility as weil as the effectiveness of the proposed design method.

关键词： Discrete-time fuzzy systems fuzzy control multiple missing control multiple missing Measurements multiple probabilistic time delays networked-control systems (NCSs) robust H∞ control stochastic systems

Pre-and post-selected Measurements with coupling-strength-dependent modulation

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Chinese Physics B 2019年第3期28卷 135-140页

作者：李兆雪邱疆冬谢林果罗兰刘雄张志友任昌亮杜惊雷 College of Physical Science and Technology Sichuan UniversityChengdu 610064China Key Laboratory of High Energy Density Physics and Technology of Ministry of Education Sichuan UniversityChengdu 610064China Chongqing Institute of Green and Intelligent Technology Chinese Academy of SciencesChongqing 400714China

Pre-and post-selected(PPS) measurement, especially the weak PPS measurement, has been proved to be a useful tool for measuring extremely tiny physical parameters. However, it is difficult to retain both the attainable highest measurement sensitivity and precision with the increase of the parameter to be measured. Here, a modulated PPS measurement scheme based on coupling-strength-dependent modulation is presented with the highest sensitivity and precision retained for an arbitrary coupling strength. This idea is demonstrated by comparing the modulated PPS measurement scheme with the standard PPS measurement scheme in the case of unbalanced input meter. By using the Fisher information metric, we derive the optimal pre-and post-selected states, as well as the optimal coupling-strength-dependent modulation without any restriction on the coupling strength. We also give the specific strategy of performing the modulated PPS measurement scheme, which may promote practical application of this scheme in precision metrology.

关键词： modulated pre-and post-selected Measurements Fisher information metric unbalanced input meter

Electrostatic-lenses position-sensitive TOF MCP detector for beam diagnostics and new scheme for mass Measurements at HIAF

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Nuclear Science and Techniques 2019年第10期30卷 63-73页

作者： Jun-Hao Liu Zhuang Ge Qian Wang Geng Wang Li-Na Sheng Wen-Wen Ge Xing Xu Peng Shuai Qi Zeng Bo Wu University of Chinese Academy of Sciences Beijing 100049China Institute of Modern Physics Chinese Academy of SciencesLanzhou 730000China School of Nuclear Science and Engineering East China University of TechnologyNanchang 330013China

A foil–microchannel plate(MCP)detector,which uses electrostatic lenses and possesses both good position and timing resolutions,has been designed and simulated for beam diagnostics and mass Measurements at the next-generation heavy-ion-beam facility HIAF in China.Characterized by low energy loss and good performances of timing and position Measurements,it would be located at focal planes in fragment separator HFRS for position monitoring,beam turning,Bq measurement,and trajectory reconstruction.Moreover,it will benefit the building-up of a magnetic-rigidity–energy-loss–time-offlight(BqDETOF)method at HFRS for high-precision in-flight particle identification of radioactive isotope beams on an event-by-event basis.Most importantly,the detector can be utilized for in-ring TOF and position Measurements,beam-line TOF Measurements at two achromatic foci,and position Measurements at a dispersive focus of HFRS,thus making it possible to use two complementary mass measurement methods[isochronous mass spectrometry at the storage ring SRing and magnetic-rigidity–time-of-flight(BqTOF)at the beam-line HFRS]in one single experimental run.

关键词： Microchannel plate Electrostatic lenses Detector Position-sensitive Time-of-flight Mass Measurements HIAF

Test Measurements for accuracy of absolute and relative GPS positioning

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中国有色金属学会会刊：英文版 2005年第S1期15卷 299-303页

作者： I. Havasi University of Miskolc Hungary

The paper, after the introduction, briefly outlines the principles of both absolute and relative GPS positioning. It deals with factors and error resources affecting the accuracy of these surveying procedures. It reviews the geodetic determination of a reference point and a base line used for the test Measurements. The study describes the completed test Measurements, and on the basis of results, it draws the conclusions for the accuracy of the investigated surveying methods. Finally, considering these accuracy measures, their possible application in mine surveying is also mentioned very shortly.

关键词： GPS surveying methods factors and errors test Measurements accuracy

TWO-DIMENSIONAL PARTICLE IMAGE VELOCIMETRY(PIV) Measurements IN A TRANSPARENT CENTRIFUGAL PUMP

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Chinese Journal of Mechanical Engineering 2005年第1期18卷 98-102页

作者： YangHua GuChuangang WangTong KeyLaboratoryforPowerMachinery＆EngineeringofMinistryofEducation ShanghaiJiaotongUniversityShanghai200030China

A special transparent centrifugal pump is designed. Detailed opticalMeasurements of the flow inside the rotating passages of a five-bladed shroud centrifugal pumpimpeller have been performed by using two-dimensional particle image velocimetry (PIV). The flow issurveyed at three load conditions q_V/q_(Vd) = 0.4, q_V/q_(Vd) = 1.0, q_V/q_(Vd) = 1.5,respectively. As a result, phase averaged PIV velocity vector maps on three planes between hub andshroud of the impeller are presented. At design load, the mean field of relative velocity ispredominantly vane congruent, showing well-behaved flow without separation. The distributions of therelative velocity on different plane along the pump shaft are very different and there is always alow velocity zone near the pressure-side of the blade at both low and design flow rate, but thelow-velocity-zone at the low flow rate is much larger than that at the design one. The studydemonstrates that the PIV technique is efficient in providing reliable and detailed velocity dataover a full impeller passage.

关键词： Particle image velocimetry (PIV) Centrifugal pump Measurements

Ensuring Uniformity of Measurements of Absorbed Doses of Intensive Photon and Electron Radiation in Radiation Technologies

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Journal of Applied Mathematics and Physics 2015年第8期3卷 942-946页

作者： V. V. Generalova A. A. Gromov O. I. Kovalenko Research Department of Metrology of Ionizing Radiation Russian Metrological Institute of Technical Physics and Radio Ingineering (VNIIFTRI) Mendeleevo Moscow Region Russia

Ensuring reliability and traceability of the unit of absorbed dose of intense photon and electron radiation, used in radiation technologies in industry, is based on the creation of a system of sample measures and methods of transmission with minimal loss of dimensional accuracy of the unit of absorbed dose from the sample tools to working dosimeters and is a necessary basis of yield growth, of increase of labour productivity and the introduction of innovative products. The measuring capabilities of the State primary special standard of power unit of absorbed dose of intensity photon, electron and beta radiation for radiation technologies and of the standards of the absorbed dose of photon and electron radiation, used for radiation monitoring of radiation pro- cesses.

关键词： Radiation Technology Absorbed Dose Ensuring Uniformity of Measurements Certified Reference Material

Gamma Dose Rate Measurements in Kuwait Using a Car-Borne GPS Integrated Dosimetric System

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World Journal of Nuclear Science and Technology 2014年第3期4卷 163-169页

作者： Darwish Al-Azmi Department of Applied Sciences College of Technological Studies Public Authority for Applied Education and Training Shuwaikh Kuwait

A mobile system comprising of a Geiger-Muller (GM) dosimeter connected with a smart phone was used for ambient gamma dose rate survey within the districts and on the roads within the state of Kuwait. While the dosimeter provides data on gamma dose rates, the smart phone provides the GPS navigation information and saves the data for subsequent analysis and mapping. The survey covered a total distance of about 2300 km within the country and 3117 data points were recorded to show the dose rate distribution on the map of Kuwait. The results show that the ambient dose rates in Kuwait range from 40 to 180 nSv.h-1 with a mean value of 103 nSv.h-1. The dosimetric system described has good potential as a tool for determining baseline background radiation dose rates in an area.

关键词： Car-Borne Dosimeter Mobile Measurements Dose Rate GM Dosimeter Kuwait